Time Travel and vicious circularity

Often times people mix models of time in order to end up with some kind of wild logically impossible sci-fi hybrid of A-theory and B-theory, which is ultimately metaphysically incoherent. We’ve all seen it being done: some show or movie or book will involve the possibility of time travel and also imply the ability to change the future by going back to the past (something which is logically impossible, and is the result of incoherent thinking altogether – at least barring some very strange conclusions about reality which I’ve explored in the John Titor post – but upon further reflection even the John Titor scenario isn’t time travel so much as world-travel). However, here’s another more subtle incoherence which often creeps into popularized time travel shows: plotlines which involve vicious circularity. By vicious circularity I mean something self-referential which lacks sufficient reason. In technical language, if P explains Q, and Q explains P, then the conjunction of P&Q remains unexplained even if both halves of the conjunct are explained. Any such self-referential explanation is going to lead to vicious circularity.

For instance, suppose that somebody from the Future comes to the Past, and tells their ‘past’ selves that they must get themselves a Ferrari. Now, while the the Future self’s having a Ferrari is explained by the Past self’s getting that Ferrari, the Past self’s getting that Ferrari is explained by the future self’s advice to get a Ferrari. The interesting question is whether such a situation is actually viciously circular. Need there be some other explanation for why the past self will get the Ferrari and why the future self has the Ferrari (the conjunct)? The only alternative is to say that the conjunct is a brute fact, and that irritates sufficient reason. Notice in this scenario it isn’t as though somebody went through some time, decided to get a Ferrari, and then went back to the past to tell themselves to get a Ferrari – there is no ‘world’ where the self who gets a Ferrari doesn’t do so precisely because her future self told her to do so. Therefore, there must be some other sufficient reason for the conjunction of those two contingent facts, such as the fact that this person freely chose to get a Ferrari at the moment she got the Ferrari, and acted as a ‘first mover’ in this restricted causal chain. Thus, the choice to get a Ferrari wasn’t determined by events prior to the choice any more than it was determined by events ‘after’ the choice, but rather the choice itself explains events both ‘after’ and prior to. So long as it is a free choice, it can fail to be entailed by past or future events, while explaining past or future events by entailing them (or in this case perhaps by acting as sufficient reason for them without entailing them, presuming that choices such as going back in time and advising the past self to get a Ferrari were also freely chosen in the Libertarian sense).

Therefore, in order for there to be a sufficient reason for a contingent and self-referential conjunct, there must be something other than the members of the conjunct which sufficiently explains the conjunct.


About tylerjourneaux

I am an aspiring Catholic theologian and philosopher, and I have a keen interest in apologetics. I am creating this blog both in order to practice and improve my writing and memory retention as I publish my thoughts, and in order to give evidence of my ability to understand and communicate thoughts on topics pertinent to Theology, Philosophy, philosophical theology, Catholic (Christian) Apologetics, philosophy of religion and textual criticism.
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4 Responses to Time Travel and vicious circularity

  1. Alex Jones says:

    Time travel is dead in the water if one considers time is an invention of the human mind, thus all those abstract arguments over time travel is a waste of energy.

    • What you just suggested is, far from escaping the issue philosophically, just a suggestion of B-theory. Thanks for the input; though I agree with B-theory, I think the most dangerous thing a person can do is flaunt education and critical thinking for the comfort of maintaining an ad hoc position (worse still, a position which promotes an abandonment of critical thinking). I submit to you that taking the issues seriously is healthier than what you recommend.

  2. Unfortunately it does not make sense to me. If you mean by ‘if Y leads from X’ something like X⊃Y (if X then Y), and if ~X (not X), then I understand that you might want to say that the statement X⊃Y is ‘true’ in a semantic and irrelevant sense. However, dealing with counterfactuals is not a waste of the philosopher’s time (especially if one is inclined to take the study of Modality seriously, which I am). Moreover, to say that ‘time’ is a product of experience is not to say that it doesn’t exist. Consider by analogy that thoughts exist as products of the mind, but nobody would say that ‘thoughts do not exist’ or ‘thoughts are irrelevant’. Similarly if Time exists only phenomenally and not ‘Ontologically’ or mind-independently, that doesn’t mean that one can avoid ‘dealing with it’. Time exists, and this itself is self-evident. The question philosophers of time are interested in is the nature of Time. As I said, I actually agree with the B-theory of time, which see’s tense as expressions of relations such as ‘earlier than’ ‘later than’ and ‘simultaneous with’. On this view, Time is phenomenal, and Time (at least in the sense of some objective ‘tense’) is not ‘flowing’ or anything of the sort. Notice, by the way, that the whole post above presumes the B-theory (since time travel is logically incoherent if Tense is an objective feature of reality). So, the whole post presumes that the passage of Time is something like what you suggest: that is a long shot from providing some reason for escaping the issues at hand.

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